Biomedicals from a soil bug: expanding scFv production host range.

Recombinant antibody fragments have a wide range of applications from research to diagnostics and therapy. Of special interest are small fragments like fragment antigen binding (Fab) or single chain fragment variables (scFv) fragments as they can be produced inexpensively in bacterial expression systems. However, recombinant production efficiencies from established production hosts vary significantly leading to inadequate yields. Gene sequences that have been synthetically adapted to match the codon preferences and respective genomic tRNA pool of the host have been used to improve yields but cannot resolve the principal problem. The development of inducible broad host range scFv expression plasmid constructs leads the way to an easy and efficient screening method for the identification of the optimal bacterial expression host.